CPLD needs clock?

Altera_Forum · ‎08-31-2009

Hello friends,

Pse forgive such dumb question.

I build myself a small PCB for EPM3064ACT100-4 for playing around.

I downloaded Quartus II 9.0, place in schematic a 7490 counter, define 1 CPLD pin as input connected to CLKA and 1 for output connected to QA. Having some experience on old fashion logic, I wired 7490 other pins to work :) so I expect to inject some MHz on In and see with scope f/2 on out :) (asumming I figure out all required CPLD settings)

Now the question is CPLD needs itself clock, or is just static - after programing I use'it as a bunch of logics "software glued" in project.

Tnx in advance,

Richard,

Altera_Forum · ‎09-01-2009

that depends upon your design

if you have only combinatorial logic and no register, then you can go without a clock.

if you have counters, and they are done with registers, then you need a clock.